Howto: Variables dependent on command-line targets

[Chad Loder]

Hello. Does GNU make provide any way to construct a
conditional which tests whether any target was specified
explicitly?

Here's what I would like to do, in pseudocode -- I can think
of some ways to achieve this (e.g., use different target names
or have the user specify a flag on the command line, but I'm
hoping I can get the kind of automagic behavior I want):

##############################################################
# two targets, this and that
#
# if user did not specify a target on command line, then assume
# the user wants a full dependency scan -- otherwise, do not
# do a dependency scan

.PHONY: all this that
all : this that

ifdef NO_TARGET_SPECIFIED_ON_COMMAND_LINE
 this : that
endif

this :
        compile this

that :
        compile that

############################################################